1. Field of the Invention
The present invention relates to an apparatus for distributing sample liquid, such as sampled blood, from a test tube into a plurality of other tubes, so that the distributed portions of the sample liquid are subjected to different items of analysis.
2. Description of the Related Art
In order to analyze sample liquid, such as blood, thereby to determine whether or not germs are contained in the liquid, and what kinds of germs they are, if contained in the liquid, it is necessary to distribute the sample liquid into a plurality of test tubes, to sort the test tubes containing the distributed portions of the liquid into groups in accordance with items of analysis, and to supply these test tubes, thus sorted, to various analyzers for performing the items of analysis on the sample liquid. Analyzers have been developed, and greatly improved analyzers have been put to practical use. The blood analyzer is a good example. Nonetheless, the distribution of a liquid sample is performed solely by human labor, as is seen in the hospitals and the research institutes. No automatic apparatus for distributing a sample liquid into a plurality of test tubes or the like have been developed.
There are problems with the distribution of a sample liquid carried out by human labor. First, the sample liquid may spill, wetting the hands of the persons engaged in the distribution of the liquid, or staining the floor. Secondly, the test tube from which the sample liquid is being distributed, or the test tubes into which the liquid is being distributed may be dropped, by mistake, onto the floor, inevitably staining the floor. Thirdly, the sample-distribution by means of manual labor requires a long time and is error-prone. Because of these problems, it is difficult to keep the sample-distribution room sufficiently clean and sanitary, or to accomplish a sufficiently high work efficiency.
The inventors hereof studied the possibility of developing an apparatus which has distribution tips, vacuum means for supplying a sample liquid into the tips from a test tube, transport means for moving the tips containing the liquid to other test tubes, and sample-distributing means for distributing the portions of the sample liquid from the tips into the test tubes. They found that such an apparatus cannot be practically employed unless it satisfies the following requirements:
(1) Each distribution tip must be set in a test tube at such an appropriate level that the sample liquid can be supplied into the tip from the test tube, without using a complex sensor (e.g., a photosensor) for detecting the surface level of the liquid in the tube or a complex control device for moving the tip to the desired level in accordance with the signal output by the sensor and representing the surface level of the liquid. PA1 (2) The distribution tips must be arranged quickly and precisely at the same intervals as the test tubes which are held in a rack and into which the sample liquid will be distributed. This is because various kinds of racks are used, each having holes for holding test tubes at regular intervals specific to the rack. PA1 (3) Measures must be taken to prevent the sample liquid from dribbling into the test tubes other than the desired ones while the distribution tips are being moved from the source tubes to the destination tubes, due to the vibration or the like applied to the distribution tips during the transportation. PA1 (4) Means must be used to replace the distribution tips with new and clean ones, smoothly and quickly, every time a sample liquid has been distributed from the tips into test tubes.